Backing Scottish independence would be a vote for "a leap into the unknown to a very uncertain destination", MP Alistair Darling has warned.

The leader of the Better Together campaign, which has rebranded itself as the No Thanks campaign, urged campaigners fighting to keep Scotland in the UK to match the emotion of the nationalist case for independence.

"Together in the days ahead we must, and we will, meet and match them in emotion as surely we have mastered them on the evidence," said Mr Darling at a pro-Union rally in Glasgow.

The Labour MP and former Chancellor of the Exchequer also stressed with 100 days to go until the referendum on September 18 "the terms of trade have changed" with Holyrood in line for "substantially enhanced powers".

He pointed out all three parties - the Conservatives, Labour and the Lib Dems - have signed up to giving more powers to the Scottish Parliament in the event of a 'No' vote.

The MP for Edinburgh South West said he wanted to use the next three months to "plan for Scotland's positive, possibility-rich future" which was "a vision that the overwhelming majority of us want".

Asked by Sky's Political Editor, Adam Boulton, if the rebranding of the No campaign stemmed from a lack of confidence in whether keeping the status quo would be better for Scotland, Mr Darling replied: "No. We believe that Scotland is better and stronger together as part of the UK.

Video:Couch Trip: Scots On Independence

"What we are saying is no thanks to the risks and costs that come from separation. In Scotland we can have the best of both worlds with a Scottish parliament with more powers, but at the same time have the opportunities and the security that comes with being a part of the UK," he told Sky News.

Asked whether it was a mistake - as his former boss Gordon Brown has said it was - to use Lego figures to try and tell the Scottish people that if they voted 'No' they could have more fish suppers, Mr Darling said: "There are lots of different ways of campaigning, some work better than others... I never actually saw it myself.

"The bigger picture is: what is in Scotland's best interests? Are we better staying part of the UK with the strength that comes with that, or should we take a leap into the unknown to a very uncertain destination?

Video:Final Countdown To Referendum Vote

"I think the majority of people in Scotland - and all the evidence suggests this - are not persuaded of the nationalist case, they are running out of arguments and running out of time in which to make them."

Leader of the Scottish National Party and First Minister of Scotland, Alex Salmond, insisted the Yes campaign was within "touching distance" of winning the referendum.

He told Sky News: "This is the first time that people in Scotland have had a democratic opportunity to vote themselves into independence.

Video:Salmond 'Made Scotland Look Small'

"It is an opportunity not just of a lifetime, it is an opportunity of the centuries, and I believe in my heart that people will grasp that opportunity."

The SNP's Fiona Hyslop, the Scottish secretary for culture and external affairs, added: "We have got every opportunity to be a normal, independent country.

"In terms of our resources we have both wealth and talent, more income per head than Japan, France and the rest of the UK."